This invention relates to the medical diagnosis of sexual impotence and, more particularly, to a device for measuring tumescence and rigidity of the penis during nocturnal erection.
In treating sexual impotence, one must initially determine whether the impotence is organic or psychogenic in origin. This determination is often difficult to make because a variety of inhibitions can cancel out sexual stimuli, making it appear as though the patient has an organic disorder when none exists. However, most men, even those suffering from psychogenic impotence, experience spontaneous erections in their sleep. The only known exception is when the person suffers from an organic disorder which prevents erection.
A number of methods have been used to detect spontaneous nocturnal erections for the purpose of distinguishing between organic and psychogenic impotence. In some cases, the patient is placed in an observation room where a nurse visually checks for an erection during the night. This method is both expensive and embarrassing to the patient, producing a strong inhibitory response which can carry over into sleep.
A sophisticated device known as a penile tumescence monitor (PTM) has been used to electronically monitor the thickness of the penis at night during sleep. However the device is very costly (approximately $4500) and of limited availability, causing it to have a substantial inhibiting effect on the patient. It is believed that this inhibition, like that caused by direct observation, can carry over into sleep and prevent spontaneous erection. The PTM also measures only an increase in thickness of the penis, referred to as the phase of "tumescence". It cannot distinguish between a penis which is just tumescent and one that is both tumescent and rigid during erection. Rigidity information is important because a penis will become tumescent prior to erection as a result of blood rushing through it.
Another known method of detecting spontaneous erections is to wrap a strip of postage stamps about the penis to form a continuous ring before going to sleep. A positive indication is obtained if the ring of stamps bursts during sleep. This method relates only to the onset of tumescence and does not indicate whether the penis has become rigid.
Therefore, it is desirable in many applications to provide a technique for detecting and accurately measuring both the degree of tumescence and the grade of rigidity of the penis during spontaneous nocturnal erection.